Factors are (prime)

2 2 2 3 3 7

Since all digits are distinct so possible factors are

1 2 3 4 6 7

1 2 4 9 7

1 3 4 6 7

1 8 9 7

2 3 4 6 7

2 4 9 7

3 4 6 7

8 9 7

Possible combinations - 8

Favorable combination (with sum as 25 i.e. 1 8 9 7) - 1

Probability = 1/8